Report. [1918]

167

abaca is the most important product. The water stored in the
stalk of the abaca leaf is a breeding place of mosquitoes.
Besides, the decaying pulp of the abaca trunk and the abundant
shade afforded by the trees aid in the propagation of mosquitoes
in the wet soil. This observation may partly explain the endemicity of malaria in Davao, where 900 cases were reported
during the year. The new immigrants were preferably attacked and with a higher rate of mortality. In Lanao malaria
is more prevalent in towns along the border of lake Lanao,
which forms many fresh water swamps, than in those in the
hinterland. While in Davao the establishment of sanitary barrios in elevated places cleared of trees will greatly reduce malaria, in Lanao a widening of the outlet of the lake (Agus River)
so that its water level is lowered by at least one meter, will
accomplish the same result. These two undertakings require
a respectable appropriation, but they are projects well worth
accomplishing. The liberal distribution of quinine among the
people was resorted to as a means, indeed not very effective,
to its control.
The cases registered in the different dispensaries during the
year are as follows:
Cases.
Agusan..................................................... 946
Bukidnon.-........-....................................... 132
Cotabato...................................................................... 2,512
Davao............................ —........................ --- —---------- 900
Lanao.......................................................................... 1,670
M isam is................................................................................... 730
Sulu................................................................................. 6,460
Surigao.......1.................................... 144
Zamboanga................................................... 1,172
Zamboanga.1,172
Total............................................................. 14,666
INFLUENZA.
The first case of influenza was recorded in the Province of
Sulu on August 3, followed in September by two cases introduced by ships from Manila, Singapore and Sandakan; October
and November saw the acme of the epidemic, attacking the health
and hospital personnel and a large part of the Philippine Constabulary force.
The disease spread to the other provinces of this division
and in November all of the provinces were practically infected.
The acme of the epidemic was reached in the latter part of
November and December. It is presumed that about 90 per
cent of the total population was attacked. The Province of